Decentralised Key Management for Delay Tolerant Networks

Advances in ubiquitous mobile computing has given rise to the pervasive deployment of physical devices embedded with sensors, software, and wireless communications that collect and exchange data. These devices are adept for deployment in environments with minimal existing infrastructure, as the devices themselves become the components of a functioning network. With the addition of mobility, these devices operate where disruption between entities is high, resulting in dynamic, fragmented, and ephemeral networks. Such networks are considered Delay Tolerant Networks (DTNs). The pervasiveness of DTN nodes, and their varied deployment environments leads to two important motivations for securing DTNs. First, the data collected, stored, and transferred between nodes can be of high value due to commercial, safety, or national security reasons. Second, persistent threats from adversaries are common. Consequently, the development of techniques to secure communications from persistent threats from within a DTN is an important area of research. One particular challenge that is foundational for securing DTN is public key management, in particular the provision of public key authentication. This is the ability for a node to verify the identity-public key binding of another node. The lack of public key authentication provides an adversary the capability of modifying the identity-public key bindings. This allows them to eavesdrop and modify contents of communications, as well as assume identities of others in the network for authentication purposes. As a result, the ability to verify the identity-public key binding is foundational to providing con dentiality, integrity, and message authentication that ensures security in a DTN. Public key authentication is achieved using Public Key Infrastructure (PKI). Centralised hierarchical PKI implementations rely on pre-established trust in a Certi cate Authority (CA), while decentralised implementations such as Pretty Good Privacy (PGP) rely on humans for trust establishment. These two methods of public key authentication